Leg Length Differences

The area of leg length discrepancy is quite controversial, with differing beliefs and approaches from practitioners of different modalities who have received different trainings. I hope this brief document is found useful.

Some LLDs can be caused by structural differences in the lengths/vertical dimensions of bones. These are called true LLDs. Some LLDs can be caused by dysfunctions in joints and their associated soft tissues, and misalignment of bones. These are called false or functional LLDs. It is important to differentiate between true and false LLDs.

In addition leg lengths can be assessed in standing, sitting, and lying prone and supine.

Another more in-depth document will be forthcoming that goes more into different methods of LLD assessment, as well as treatment, common errors and misunderstandings.

PRACTICAL BACKGROUND BASICS

Find level area of floor surface to work on. Check with a spirit level in many directions and positions.

Check that the lighting in the room is adequate.

Work out which eye is your dominant eye if you don't already know. (Hold hands to form a circle at arms length. Look through circle at a specific object. Close one eye. Can you still see the object? Close other eye. Can you still see the object? The dominant eye is whichever eye you can still see the object with when the other eye is closed.

You will be comparing structures for symmetry. To do this you must place your dominant eye:

In the same plane as the two structures you are comparing

Equidistant from the two structures you are comparing

If you don't have these points right it won't work!

BOTTOM LINE – PRELIMINARY STRUCTURAL ASSESSMENT – PRE-TREATMENT

STANDING ASSESSMENT

Get person to STAND on the level area with their back facing towards you. Ensure they are standing with weight evenly on both feet, and the inside edges of their feet parallel.

Ensure the light source of the room is shining across the body of the person.

Stand a distance back and directly behind the client and look at their overall alignment.

Look at feet

Are ankles straight or do they roll inwards?

Is one calf muscle larger?

Look at whole body – is spine straight?

Are lower and middle back muscles symmetrical in development?

Does one side look thicker or wider?

(Usually there is better development of lumbar muscles on the short leg side.)

Are Gluteal folds horizontal and the same on both sides?

Are hip bones horizontal?

Get the client to breathe in and then out fully – does the most medial (towards the spine) part of the curve between the hip bone (ilium) and the lower lateral ribs look even on both sides?

On women, are the dimples at the back of the hips level?

Is lower back straight (vertical) and symmetrical when compared with the hips?

Are there any sideways curves?

Mid-back – does the spine look straight?

Is it directly in line with the lumbar spine?

Is there any misalignment in the whole of the middle and lower back?

In men the most reliable indicators are the lumbar muscles.

In women one hip seems fuller, or more rounded, than the other, and there is unlevelness of the dimples at the back of the hips.

Love handles are not good landmarks.

Now move within arms reach of the person.

Palpate Iliac Crests and site Iliac Crests with your dominant eye in the correct position, in the same plane as the iliac crests, and equidistant between the two iliac crests. Note which if any is higher/lower.

For this palpation and all future palpations of bony landmarks, it is often helpful to first locate with a broader flatter aspect of palm or thumb and fingers in a spiralling motion, and then to refine down to just thumb pads. Then spiral in to locate the prominence which projects outwards horizontally. Roll your thumbs or fingers down below the landmark, and up above, and inside, and outside, to come to a clear three dimensional assessment of where the landmark is. Repeat with eyes closed and open if necessary a few times. Eventually this will all be very quick, but take your time in the beginning. It helps to look away or close your eyes so you are not moving your thumbs/fingers where you want to see them, but where the bony prominence actually is.

Palpate and sight Posterior Superior Iliac Spines (PSISs).

Move to the front of the client (or get them to turn around 180 degrees).

Palpate and sight Anterior Superior Iliac Spines (ASISs)

If Iliac Crests, PSISs and ASISs are all lower on one side, this is a strong preliminary indicator of the lower side being the side of the short leg.

Note down your observations on your written record.

Carefully observe the Medial Malleoli of each ankle and their relationship. Having your head in the same plane as the two structures you are comparing in this instance necessitates getting your head way down on the ground. I recommend doing this from both directly in front of the person, and from directly behind the person, from close up, and well back.

DETERMINING MEASUREMENT OF LLD

Put blocks/shims/lift materials of known thicknesses under the shorter leg first, until all above indicators seem even. Remember person must stand with weight on both legs equally, with both feet still pointing straight ahead. (1mm to 1.25 mm shims are recommended. Alternatively, use the lift materials of varying thicknesses available from Podiatry suppliers.)

Then put the same height of material under the longer leg, to exaggerate the pattern of distortion and to check your previous perception. Reassess all above indicators.

Assess all changes from close up and from standing back.

If rear foot pronation is observed, manually correct it as the person stands, get them to hold it, and reassess 9. to 16. above. This is very important, as pronation is common on the side of the short leg.

. TREATMENT

Now assess in prone and supine and treat any functional pelvic lesions. If being very thorough, then assess and treat all lesions from waist down, or simply all lesions in whole body!

Particular attention should be paid to Anterior and Posterior Iliac Rotation, Superior and Inferior Iliac Shear, and Inflare/Outflare Dysfunctions.

REASSESS with points 6. to 20. There are three possibilities.

The measurement of the LLD is the same or greater than it was originally. Then the person definitely has a true LLD. The second measurement is considered to be the most accurate.

The measurement of the LLD is less but landmarks are still unlevel. Then the patient may have a true LLD that also had a functional component. The second measurement is considered to be the most accurate.

The measurement now shows no difference. In this case the difference was purely of functional origin with no structural component.

Do not implement lift therapy on the first session. Let the person determine if they are happy with the result from treatment as is, and if their pelvic dysfunctions return.

On the second session, persons in category B) or C) in point 23. above who re-present with the same pelvic dysfunctions may require lift therapy.

Persons in category B) of point 23. may require lift therapy if the true LLD exceeds 4 mm. This is a rough guide, and some practitioners find that even 2mm or less is significant for some people. Alternatively, medium-term monitoring or CT scan confirmation of LLD may be appropriate.

Persons in category C) of point 23. do not require lift therapy, but rather correction of functional problems.

IMPLEMENTING LIFT THERAPY

Usually the amount of lift implemented is slightly less than half of the true LLD. This can be gradually increased over time to bring the final amount of lift within 4 mm of the true LLD as determined by the above indirect method or by CT scan.

This leaves a safety margin for error if the indirect method is used, and allows for fixed structural changes that may be part of how the body grew with its short leg. On the other hand, some people may not feel right until the full amount is corrected, which would leave their hip levels in standing the same as what they have been in sitting there whole lives, unless they have considerable assymetry of the pelvis as well!

Up to 9 mm of lifting can be implemented at each time.

It is helpful if the person has a full treatment and then puts on their new footwear immediately when they get off the table and walk it in.

Full sole lifts are preferable to simple heel lifts, as they preserve peri-talar mechanics and stability and prevent problems of forefoot strain developing or worsening.

The following is quoted from Patterns of facilitation and inhibitions of the lower extremities and pelvis by Manual Therapy Institute:

In general, it is possible to fit a full length lift of up to 5 mm inside many shoes worn by males. For females, good luck! For lift heights between 5-8 mm, it is recommended to build up the sole of one shoe. For heights in excess of this, it is recommended to raise the sole on the short leg to 8mm and reduce the sole on the long leg to the appropriate height.

People must be cautioned that lift therapy use is continuous and must be incorporated into all footwear..

Orthotic devices should only be employed once the joints and fasciae of the foot and ankle have been maximally corrected. If the amount of lift required is small enough, they can be adhered/incorporated into/with the full sole lift. If the amount is greater, the lifting component can be added to the sole of the shoe.

REFERENCES

Overcome Neck and Back Pain by Kit Laughlin

Personal communication with Kit Laughlin

Patterns of facilitation and inhibitions of the lower extremities and pelvis by Manual Therapy Institute